Sifters for grain and chemical industries

ABSTRACT

A sifter or separator particularly for use in connection with grain milling machines provides for continuous circulation of air along a closed pathway within the apparatus. The material to be sifted is introduced in said circulatory stream of air at one point thereof, while the coarse portion of the material is removed from said stream by impingement against a rotary screen which permits finer particles of the material to pass into a cyclone where they are removed from the air stream by centrifugal action and gravity. Inlet and outlet valves are of the type which when operated permits passage of the material while at the same time substantially preventing passage of air regardless of operative position.

United States Patent 1 1 1111 3 3,837,483

Noll Sept. 24, 1974 SIFTERS FOR GRAIN AND CHEMICAL 974,004 9/1950 France209/250 INDUSTRIES 1,003,661 3/1957 Germany 209/31 [76] Inventor: g g ggz Primary Examiner-Robert Halper p g t t torney tggnt, or firml-lill,Gross, Simpson, Van [22] Filed: Mar. 22, 1973 Santen, Steadman, Chiara &Simpson [21] App]. No.2 343,909

57 ABSTRACT 52] us. c1 209/30, 209/144, 209/271 A Sifter 9r SeparatorParticularly for use in connection 51 Int. (:1 B0713 9/00 with grainmilling machines provides for continuous 58 Field of Search 209/144, 30,31-37, Circulation of air along a closed P y within the 209050, 271apparatus. The material to be sifted is introduced in said circulatorystream of air at one point thereof,

5 References Cited while the coarse portion of the material is removedUNITED STATES PATENTS from said stream by impingement against a rotaryscreen which permits finer particles of the material to 523,335 7/1894Dodge 209 250 x pass into a Cyclone where they are removed from the2,635,309 4/1953 Smith..... 2,713,977 7/1955 Noll air stream bycentrifugal action and gravity. Inlet and outlet valves are of the typewhich when operated per- 3,0l0,576 11/1961 Marte 209/35 m1ts passage ofthe materlal while at the same t1me FOREIGN PATENTS OR APPLICATIONSsubstantially preventing passage of air regardless of 681,211 8/1939Germany 209/35 operative position. 782,760 9 1957 Great Britain 209/21'892,242 12/1951 Germany 209/37 2 Clam, 3 Drawlng Figures SIFTERS FORGRAIN AND CHEMICAL INDUSTRIES This invention relates to a sifter orseparator for a variety of different materials although of particularadvantage in connection with grain milling machines for the purpose ofseparating the coarser particles of grain from the fine ingredients.

An object of the invention is to provide a sifter or separator of thekind indicated which requires very little space without loss ofefficiency.

A further object of the invention is to provide a sifter of thetype-indicated in which the material to be sifted is entrained by astream of air which circulates along a closed pathway wholly within theapparatus, thus eliminating the need for air filters.

Another object of the invention is to provide a sifter of the kindindicated which is inexpensive to manufacture and to operate,particularly due to the absence of air filters and consequent need forcleaning and replacement of the same.

Other objects and advantages of the invention will become apparent fromthe following detailed description thereof.

A preferred embodiment of the invention is described below withreference to the accompanying drawing in which FIG. 1- is a diagrammaticperspective view of the sifter or separator,

FIG. 2 is a diagrammatic top plan view of the same, and

FIG. 3 shows, on a larger scale, a vertical section through the sifteror separator on line Ill-Ill in FIG. 2.

In the drawing, a housing comprises two parallel vertical end walls l2,14 which are interconnected along their edges by a side wall 16 theupper portion of which is cylindrical and extended downwardlysubstantially in the form of a V. Along the edges of said V- shapedextension of the side wall the end walls 12, 14 are inclined downwardlytowards each other to thus form with the side wall 16 a funnel-shapedportion 18 at the bottom of the housing 10. Said funnel-shaped portion18 opens into a bottom pipe 20 in which a control valve 22 is mounted.The housing 10 is supported on four legs 24 and abase plate 26, or inany other suitable manner.

A horizontal shaft 30 is mounted in suitable bearings 32 in the end wall12 of housing 10 and extends therethrough perpendicularly to the endwalls 12, 14 at the center of the upper cylindrical portion of thehousing 10. Said shaft 30 carries on its outer end portion a pulley 34and on its other end within the housing 10 a circular screen 35 whichthus is rotatable on the axis of the shaft 30 when a source of drivingpower is applied to the pulley 34 as, for example, by means of a motor,indicated at 36, a drive pulley 38 and a V-belt 40.

A U-shaped pipe or tube 44 is supported by a bracket 46 secured to theupper portion of the housing 10 and extending upwardly therefrom. Ahorizontal leg 48 of said pipe extends into the housing 10 through theend wall 12 thereof into close vicinity of the screen 35. The other leg50 of the U-shaped pipe is secured to and communicates with the interiorof a ventilator 52 which comprises a housing 54 in which an impeller 56is mounted for rotation on a vertical shaft 58 of a drive motor 60secured to the top wall of the ventilator housing 54. A supply pipe 62communicates with the leg 50 of the U-shaped pipe 44 and is providedwith a control valve 64.

Below the ventilator 52 a cyclone 66 is disposed which comprises anupper cylindrical portion 68 with a top closure 70 and a downwardlytapering lower portion 72 with a bottom outletpipe 74 provided with acontrol valve 76. The cyclone 66 is supported on a horizontal pipesection 78 which is secured to the cylindrical upper portion 68 of thecyclone 66 and to the end wall 14 of the housing 10 to establishcommunication between the interiors of said cyclone 66 and housing 10.

Within the housing 10 the pipe section 78 terminates in a conical member80, the wide end of which is disposed in close vicinity to the screen 35and in axial alignment with the leg 48 of the U-shaped pipe 44. The pipesection 78 is curved in the horizontal plane as indicated by dottedlines in FIG. 2 so as to provide an inlet to the cyclone 66 which isdirected tangentially of said cyclone. A pipe section extends downwardlyfrom the bottom wall of the ventilator 52- centrally thereof into thecyclone 66 within the cylindrical portion 68 thereof, and the portion ofsaid pipe section 80 disposed within the cyclone 66 is provided with anumber of perforations 82, as shown.

The valves 64, 22 and 76 are of the type, well known in the art, whichwhen rotated either continuously or intermittently permit passage ofgranular material while at the same time in any rotary positionsubstantially preventing passage of air. Said valves may be operatedmanually or automatically in any desired sequence by suitable means (notshown).

In operation when the impeller 56 is rotated by its drive motor 60 astream of air is forced out through the U-shaped pipe 44 towards therotating screen 35 and through pipe 78 of cyclone 66, perforations 82and back through pipe 80 into the ventilator 52. In passing the openinner end of supply pipe 62 said stream of air carries with it thematerial from said supply pipe 62, and when said entrained materialforcefully hits the screen 35, coarser particles in the material areprevented from passing through said screen and fall downwardly in thehousing 12 towards the valve 22. Finer particles of the material passthrough the rotating screen 35 and enter through the funnel-like portion80 into the pipe 78 from where they pass tangentially into the cyclone68 and are flung due to centrifugal action along the interior wall ofthe cylindrical portion 68 of said cyclone 66 whereupon they graduallydrop downwardly through the tapered portion 72 of the cyclone toward thevalve 76. The air thus substantially free from entrained material isreturned to the ventilator 52 and recirculated along the path indicatedabove.

It is obvious, therefore, that due to the continuous circulation of theair within the apparatus and the continuous removal of entrainedmaterial in the housing 10 and the cyclone 66 there is no need for anyfilters at any place in the apparatus. This is one of the outstandingadvantages of the present invention, naturally resulting insubstantially reduced manufacturing and operating costs and in greatlyreduced space requirements, all without any detrimental effect on theefficiency of the apparatus.

The invention is not limited to the embodiment shown and described butnumerous modifications are feasible within the limitations of theappended claims.

What I claim is:

l. A sifter for separating coarse and fine particles from each other,particularly in connection with grain milling machines, comprising a. ahousing mounted on a support base and having a bottom outlet,

b. a sifter screen of substantially flat configuration,

c. means supporting said screen within said housing for rotation on asubstantially horizontal axis,

d. means for rotating said screen on said axis,

e. a ventilator housing disposed adjacent to said screen housing,

f. a ventilator mounted in said ventilator housing for rotation on avertical axis,

g. ventilator drive means connected with said ventilator,

h. a cyclone beneath said ventilator housing and having a circularcross-section in a horizontal plane and a bottom outlet,

i. a tubular member secured to said ventilator housing and extendingdownwardly therefrom into'said cyclone centrally of said ventilator andsaid cyclone and provided with a plurality of apertures distributedaround the circumference of the portion of said tubular member extendinginto said cyclone,

j. a substantially U-shaped tubular member connecting the interior ofsaid ventilator housing with the interior of said screen housing, oneleg of said U- shaped tubular member ending close to said screen at adistance from the center of said screen,

k. a pipe section having one end in close vicinity to the opposite sideof said screen from said one leg of the U-shaped tubular member andbeing aligned therewith, the other end portion of said pipe sectionbeing secured to said cyclone and opening into the same in a tangentialdirection thereof,

l. a supply pipe connecting said U-shaped tubular member with a sourceof supply for the material to be sifted, and

m. a valve in each of said supply pipe and said bottom outlets of thescreen housing and the cyclone, said valves being of the typesubstantially preventing air passage in all operative positions whilebeing operative to permit passage of granular material, whereby a streamof air propelled by said ventilator from said ventilator housing passesin a closed pathway through said U-shaped tubular member into saidscreen housing, through said rotating screen, into and through said pipesection, tangentially into said cyclone to be whirled around along thecylindrical interior wall thereof, through said plurality of aperturesand back through said tubular member into the ventilator housing therebyentraining the material to be sifted from said supply pipe and causingcoarse particles in said material to impinge against said rotatingscreen and fall downwards in the screen housing toward the bottom outletthereof, while finer particles pass through the screen and into thecyclone to be subjected to centrifugal action and fall downwardly towardthe bottom outlet of said cyclone.

2. A sifter for separating coarse and fine particles from each other,particularly in connection with grain milling machines, comprising aventilator, a housing enclosing a rotary disc type screen, and acyclone; tubular means interconnecting said ventilator, screen housingand cyclone so as to form a closed pathway through said elements; supplymeans for controlled introduction of the material to be sifted into saidpathway; and valve means in said supply means, said screen housing andsaid cyclone, said valve means being of the type substantiallypreventing passage of air therethrough in all operative positions whilepermitting controlled passage of sifted material, and said tubular meanscomprising a first U-shaped tubular element connecting said ventilatorwith said screen housing and ending in close vicinity to one side ofsaid rotary screen, a second tubular element aligned with the outletportion of said first U-shaped tubular element and extending from thevicinity of the other side of said screen into said cyclone tangentiallyof said cyclone, and a third tubular element providing communicationbetween said cyclone and said ventilator and having a portion extendinginto said cyclone to a level below said second tubular element and beingprovided in the downwardly extending portion with a plurality of small

1. A sifter for sepaRating coarse and fine particles from each other,particularly in connection with grain milling machines, comprising a. ahousing mounted on a support base and having a bottom outlet, b. asifter screen of substantially flat configuration, c. means supportingsaid screen within said housing for rotation on a substantiallyhorizontal axis, d. means for rotating said screen on said axis, e. aventilator housing disposed adjacent to said screen housing, f. aventilator mounted in said ventilator housing for rotation on a verticalaxis, g. ventilator drive means connected with said ventilator, h. acyclone beneath said ventilator housing and having a circularcross-section in a horizontal plane and a bottom outlet, i. a tubularmember secured to said ventilator housing and extending downwardlytherefrom into said cyclone centrally of said ventilator and saidcyclone and provided with a plurality of apertures distributed aroundthe circumference of the portion of said tubular member extending intosaid cyclone, j. a substantially U-shaped tubular member connecting theinterior of said ventilator housing with the interior of said screenhousing, one leg of said U-shaped tubular member ending close to saidscreen at a distance from the center of said screen, k. a pipe sectionhaving one end in close vicinity to the opposite side of said screenfrom said one leg of the U-shaped tubular member and being alignedtherewith, the other end portion of said pipe section being secured tosaid cyclone and opening into the same in a tangential directionthereof, l. a supply pipe connecting said U-shaped tubular member with asource of supply for the material to be sifted, and m. a valve in eachof said supply pipe and said bottom outlets of the screen housing andthe cyclone, said valves being of the type substantially preventing airpassage in all operative positions while being operative to permitpassage of granular material, whereby a stream of air propelled by saidventilator from said ventilator housing passes in a closed pathwaythrough said U-shaped tubular member into said screen housing, throughsaid rotating screen, into and through said pipe section, tangentiallyinto said cyclone to be whirled around along the cylindrical interiorwall thereof, through said plurality of apertures and back through saidtubular member into the ventilator housing thereby entraining thematerial to be sifted from said supply pipe and causing coarse particlesin said material to impinge against said rotating screen and falldownwards in the screen housing toward the bottom outlet thereof, whilefiner particles pass through the screen and into the cyclone to besubjected to centrifugal action and fall downwardly toward the bottomoutlet of said cyclone.
 2. A sifter for separating coarse and fineparticles from each other, particularly in connection with grain millingmachines, comprising a ventilator, a housing enclosing a rotary disctype screen, and a cyclone; tubular means interconnecting saidventilator, screen housing and cyclone so as to form a closed pathwaythrough said elements; supply means for controlled introduction of thematerial to be sifted into said pathway; and valve means in said supplymeans, said screen housing and said cyclone, said valve means being ofthe type substantially preventing passage of air therethrough in alloperative positions while permitting controlled passage of siftedmaterial, and said tubular means comprising a first U-shaped tubularelement connecting said ventilator with said screen housing and endingin close vicinity to one side of said rotary screen, a second tubularelement aligned with the outlet portion of said first U-shaped tubularelement and extending from the vicinity of the other side of said screeninto said cyclone tangentially of said cyclone, and a third tubularelement providing communication between said cyclone and said ventilatorand having a portion extending iNto said cyclone to a level below saidsecond tubular element and being provided in the downwardly extendingportion with a plurality of small apertures.